Food Processing Vat With Zoned Temperature Control

ABSTRACT

A food processing vat is provided with a zoned heat transfer system that provides zoned temperature control to the vat. The zoned heat transfer system selectively transmits heat to or removes heat from different portions of a bottom wall and/or side wall(s) of the vat. A heat transfer fluid may be directed through the zoned heat transfer system along a flow path that is selected based on a target size and/or a target temperature of a batch of food product being processed in the vat.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority from U.S. Provisional PatentApplication Ser. No. 61/325,612 filed on Apr. 19, 2010, the entirety ofwhich is expressly incorporated by reference herein.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to food processing vats and, more particularly, totemperature control systems of food processing vats.

2. Discussion of the Related Art

Temperature control systems for use in food processing vats are known inthe food processing industries. Such systems are widely used inequipment for processing liquid or semi-liquid food products, such ascheese vats.

Temperature control systems used in cheese vats typically have hollowjackets that cover sidewalls of the vat. Steam, heated liquid, or coolliquid is introduced into the jacket. Introducing steam or heated liquidinto the jacket warms the sidewalls of the vat and thus also warms thevat contents. Introducing cool liquid into the jacket cools thesidewalls of the vat and thus also cools the vat contents.

SUMMARY OF THE INVENTION

The inventors have recognized that in food processing vats, differentparts of the vat influence the food being processed in the vats indifferent ways. The inventors have also recognized that in cutting,stirring, and/or agitating vats, sloshing and splashing of the foodbeing processed produces thin films or layers of the food that cling toand run down a splash-zone portion of an inner surface of the vat. Theinventors have further recognized that in temperature controlled vats,the splash-zone tends to heat or cool the food layers running down themmore quickly than the main mass of food that is heated or cooled by thecorresponding portion of the vat, which may lead to overheating orovercooling of the food layers running down the splash-zone. The presentinvention contemplates a zoned heat transfer system that provides zonedtemperature control and addresses these and other inventor-identifiedproblems and drawbacks of the prior art.

In accordance with one aspect of the invention, a vat is provided thatincludes a bottom wall, side walls extending upwardly from the bottomwall, and a zoned heat transfer system for selectively transmitting heatto or removing heat from different portions of at least one of thebottom and side walls of the vat. The zoned heat transfer system mayinclude at least one lower heat transfer zone and at least one upperheat transfer zone. The lower heat transfer zone may extend across thevat bottom wall and the upper heat transfer zone may extend across eachof the vat side walls. This allows less heating or less cooling to occurin portions of the vat that are more susceptible to overheating orovercooling the vat contents.

In accordance with another aspect of the invention, multiple lowerand/or multiple upper heat transfer zones may extend across the vatlower and side walls, respectively. The multiple lower and/or upper heattransfer zones may include at least a pair of lower and a pair of upperheat transfer zones. In one embodiment, intermediate heat transfer zonesare provided between the lower and upper heat transfer zones. Respectivepairs of the heat transfer zones may be controlled separately withrespect to other pairs of the heat transfer zones. The two heat transferzones of each simultaneously controlled pair may be provided at oppositeside walls of the vat, so that by controlling the respective pairs ofzones, temperature changes along the height of the vat are mirrored onboth sides of the vat, as a reflection about a longitudinally extendingcenterline of the vat. In another embodiment, each of the multiple heattransfer zones may be controllable separately with respect to the otherheat transfer zones, and/or in pairs with respect to other pairs of heattransfer zones. Separate controllability of heat transfer activity ofthe various heat transfer zones may help control instances ofoverheating or overcooling that may occur at about the same height ondifferent walls of the vat.

In accordance with another aspect of the invention, transmitting heat toor removing heat from different portions of the vat is accomplished bycirculating a heat transfer fluid through the zoned heat transfersystem. The heat transfer fluid may be heated for transmitting heat tothe at least one of the bottom and side walls of the vat and/orunheated, optionally cooled, for removing heat from the at least one ofthe bottom and side walls of the vat. A diverter system may direct flowof the heat transfer fluid through the zoned heat transfer system. Thediverter system selectively may direct the heat transfer fluid to flowthrough various heat transfer zones and prevent the heat transfer fluidfrom flowing through other heat transfer zones, based on therequirements for processing a particular batch of food product, whichmay provide for a substantial amount of control and tunability to theheat transfer system so that the vat can accommodate vastly differentmaterials and/or processes.

In accordance with another aspect of the invention, the heat transferzones are connected to each other in series, such that a heat transferfluid flows sequentially through the respective heat transfer zones, andthe diverter system controls which one(s) of the heat transfer zonesthat the heat transfer fluid can flow through. Additionally or instead,the heat transfer zones may be connected to each other in parallel, suchthat a heat transfer fluid is divided and simultaneously flows throughthe respective heat transfer zones. Each of the heat transfer zones mayinclude a heat exchanger and the respective inlets and outlets of theheat exchangers may be connected to each other, with interveningdiverters of the diverter system, so as to establish the series and/orparallel connections of the heat transfer zones, allowing for controlversatility to accommodate different materials and/or processes.

In accordance with another aspect of the invention, a method ofprocessing food in a vat includes determining (i) a target size of abatch of food product to be processed in a vat, and (ii) a targettemperature for processing the batch of food product within the vat. Aheat transfer fluid is delivered to a zoned heat transfer system of thevat for transmitting heat to or removing heat from the batch of foodproduct and is directed through the zoned heat transfer system along aflow path that is selected based on at least one of the target size andtarget temperature of the batch of food product. A temperaturedifferential may be established between two heat transfer zones of theheat transfer system. A temperature of one of the two heat transferzones may be heated or cooled to a temperature that defines a firstcomponent of the temperature differential, which substantiallycorresponds to the target temperature for processing the batch of food,allowing for control versatility to accommodate different batches whilereducing the likelihood of overheating or overcooling layers of the foodthat may be running down the splash-zone toward the rest of the food.

Various other features, objects, and advantages of the invention will bemade apparent from the following description taken together with thedrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The drawings illustrate the best mode presently contemplated of carryingout the invention.

In the Drawings:

FIG. 1 is an isometric view from above and in front of a vat systemincorporating a zoned heat transfer system in accordance with thepresent invention;

FIG. 2 is an isometric view from above and in back of the vat system ofFIG. 1;

FIG. 3 is a sectional view of the vat system of FIG. 1, taken at line3-3 of FIG. 1;

FIG. 4 is another sectional view of the vat system of FIG. 1;

FIG. 5 is a schematic isometric view of a shell incorporating a zonedheat transfer system;

FIG. 6 is a schematic front elevation of the zoned heat transfer systemof FIG. 5;

FIG. 7 is partially schematic sectional view of the vat system of FIG.1;

FIG. 8 is another partially schematic sectional view of the vat systemof FIG. 1;

FIG. 9 is a sectional view of a heat exchanger of FIG. 8, taken at thecurved line 9-9 of FIG. 8;

FIG. 9A is a close-up sectional view of the heat exchanger of FIG. 9,taken at the curved line 9A-9A; and

FIG. 10 is a schematic view of a zoned heat transfer system.

DETAILED DESCRIPTION OF THE INVENTION

FIGS. 1 and 2 illustrate a vat system 5 that can be used for processingfood and related products (collective referred to as “vat contents 9”)by mechanically manipulating and heating or cooling the vat contents 9,depending on the particular food or related product being processed. Ina representative application, the vat system 5 may be used in theproduction of cheese, although it is understood that the vat system 5may be used in processing other types of food products. It is alsounderstood that the vat system 5 may be used for processing non-foodliquid or semi-liquid compositions. The vat system 5 includes a vat 7that has an agitation system 40 which performs the mechanicalmanipulations tasks by delivering power through a pair of drives 42(FIG. 2) that rotate a pair of shafts 45 (FIG. 3) upon which bladeassemblies are mounted, and a zoned heat transfer system 50 to performsuch heating and/or cooling to provide zoned temperature control to thevat 7.

Referring now to FIGS. 1-4, vat 7 defines an enclosure having a top wall10, a bottom wall 11, and side walls 14, 15, all of which extendlongitudinally between a pair of end walls 18 and 19. The walls 10, 11,14, 15, 18, 19 are multilayered, having an outer jacket 20 and an innershell 25 (FIGS. 3 and 4) that are spaced from each other. Insulation andvarious components of the zoned heat transfer system 50 are housedbetween the jacket 20 and shell 25. Shown best in FIG. 3, the shell 25is the inmost structure of the vat 7, so that its inner surfacesurrounds and defines an outer periphery of a void or inside space 8within the vat 7. A lower part of the inside space 8 resembles twohorizontal parallel cylinders that transversely intersect each other,being defined by a bottom wall 26 of the shell 25 that has a pair ofarcuate depressions which extend along the length of the vat 7, onopposing sides of a longitudinally extending raised middle segment. Fromthe opposing sides of the shell bottom wall 26, opposing shell sidewalls 27, 28 extend in an outwardly bowed manner, arching away from eachother in a transverse direction of the vat 7. A shell top wall 29 arcsgradually between top edges of the shell side walls 27, 28 and definesan upper perimeter of the inside space 8 of vat 7.

Referring now to FIGS. 3 and 4, the inside space 8 of vat 7 and the foodproduct, in other words the vat contents 9, are heated and/or cooledwith the zoned heat transfer system 50 by selectively transmitting heatthrough or removing heat from different portions of one or more of thevat bottom and side walls 11, 14, 15, respectively. The amount of heatto transmit to or remove from the vat contents, as well as theparticular portions of the vat 7 from which to transmit heat to orremove heat from, are selected based on a target batch size and/ortarget temperature of the vat contents, explained in more detailelsewhere herein.

Referring now to FIGS. 5 and 6, the zoned heat transfer system 50 ofthis embodiment has multiple heat transfer zones. Toward the bottom ofthe vat 7, two lower heat transfer zones 51, 52 are defined along thebottom wall 26 of the shell 25. The lower heat transfer zones 51, 52 arepositioned to direct heat transfer activity generally vertically upthrough the bottom of the vat 7, with lower heat transfer zone 51 beingpositioned below one agitator shaft 45 (FIG. 3) and lower heat transferzone 52 being positioned below another agitator shaft 45 (FIG. 3).

Still referring to FIGS. 5 and 6, a pair of intermediate heat transferzones 53, 54 is positioned laterally beyond the lower heat transferzones 51, 52. Intermediate heat transfer zone 53 is adjacent the lowerheat transfer zone 51 and extends across (i) an upper and/or outerportion of the bottom wall 26 shown on the left side of FIG. 6, and (ii)a lower and/or inner portion of the sidewall 27. Intermediate heattransfer zone 54 is adjacent the lower heat transfer zone 52 and extendsacross (i) an upper and/or outer portion of the bottom wall 26 shown onthe right side of FIG. 6, and (ii) a lower and/or inner portion of thesidewall 28. This arrangement provides the intermediate heat transferzones 53, 54, with generally obliquely facing orientations, whereby theintermediate heat transfer zones 53, 54 direct heat transfer activitygenerally obliquely through the inside space 8, toward the middle of vat7.

Still referring to FIGS. 5 and 6, a pair of upper heat transfer zones55, 56 is positioned laterally beyond and also higher than the lower andintermediate heat transfer zones 51, 52, 53, 54, respectively. Upperheat transfer zone 55 is adjacent the intermediate heat transfer zone 53and extends up the sidewall 27, toward the top wall 29. Upper heattransfer zone 56 is adjacent intermediate heat transfer zone 54 andextends up the sidewall 28, toward the top wall 29. The upper heattransfer zones 55, 56 are arranged in generally vertical orientations,so that they direct heat transfer activity generally transversely fromthe sides of the vat 7, toward each other. The upper heat transfer zones55, 56 extend between upper and lower halves of the vat 7. In thisembodiment, lower edges of the upper heat transfer zones 55, 56 areprovided at a height that is about 35% of an overall height. Upper edgesof the upper heat transfer zones 55, 56 are provided at a height that isabout 80% of the overall height of the inside space 8 of vat 7. It isunderstood, however, that there can be any number of the various heattransfer zones and that the relative heights and positions may be otherthan those described, so long as the desired zoned temperature controlmay be achieved for a particular implementation.

Referring now to FIGS. 7 and 8, in this embodiment, the zoned heattransfer system 50 includes heat exchangers 70, a diverter system 80,controls 90, and a heat transfer fluid 100. A heat exchanger 70 isprovided within each of the lower, intermediate, and upper heat transferzones 51, 52, 53, 54, 55, and 56, respectively. Shown best in FIGS. 9and 9A, each heat exchanger 70 has a pair of stacked sheets, with atleast parts of the sheets being spaced from each other and defining avoid space 105 therebetween, through which the heat transfer fluid 100is conveyed. The inner sheet of this heat exchanger 70 is the shell 25and the outer sheet 72 overlies or is outside of the outwardly facingsurface of the shell 25.

Referring now to FIG. 10 which schematically shows the zoned heattransfer system 50 in an un-curled or flattened position, each heatexchanger 70 has an inlet 75 through which the heat transfer fluid 100enters the heat exchanger 70 and an outlet 78 through which the heattransfer fluid 100 exits the heat exchanger. These heat exchangers 70include longitudinally extending baffles 79 that connect the outer sheet72 to the shell 25. Baffles 79 are positioned within the heat exchanger70 so as to direct the heat transfer fluid 100 back and forth throughthe heat exchanger 70, while allowing both the inlet 75 and outlet 78 tobe mounted to the heat exchanger 70 at the same side or end of the vat7. In another embodiment, the inlets 75 and outlets 78 are provided atdifferent sides or ends of the vat 7. In such other embodiment, the heatexchanger 70 does not include baffle 79, or the baffle 79 is configuredto allow the heat transfer fluid 100 to enter and exit opposing ends ofthe heat exchanger 70.

Still referring to FIG. 10, in this embodiment, adjacent heat exchangers70 and thus adjacent ones of the lower, intermediate, and upper heattransfer zones 51, 52, 53, 54, 55, and 56, respectively, are connectedin series with each other so that the heat transfer fluid 100 flowssequentially through the lower, intermediate, and upper heat transferzones 51, 52, 53, 54, 55, and 56, respectively. This is done byconnecting an outlet 78 of a heat exchanger 70 to an inlet 75 of adownstream heat exchanger 70, whereby the inlet 75 of the downstreamheat exchanger 70 intakes the heat transfer fluid 100 that is dischargedfrom the preceding outlet 78 of the upstream heat exchanger 70. In thisparticular embodiment, a first series connection is made between theheat exchangers 70 of the lower, intermediate, and upper heat transferzones 51, 53, 55, toward the left-hand side of FIG. 10. A second seriesconnection is made between the heat exchangers 70 of the lower,intermediate, and upper heat transfer zones 52, 54, 56, toward theright-hand side of FIG. 10.

Referring now to FIGS. 7, 8, and 10, the heat transfer fluid 100 in thisembodiment is divided into two distinct flow paths that are mirroredabout a longitudinally extending centerline of the vat 7, flowingthrough (i) the lower heat transfer zone 51 and one or both of theintermediate and upper heat transfer zones 53, 55, and (ii) the lowerheat transfer zones 52 and one or both of the intermediate and upperheat transfer zones 54, 56, respectively. In one embodiment, both of thelower heat transfer zones 51, 52 are controlled, heated and/or cooled inunison with each other, serving as a center of heat transfer activitywithin the vat 7. The additional heat transfer activity of theintermediate and upper heat transfer zones 53, 54, 55, 56 is mirroredabout such center of heat transfer of the lower heat transfer zones 51,52. This is done by controlling the intermediate and upper heat transferzones 53, 54, 55, 56 in pairs to selectively permit series flow of theheat transfer fluid 100 from the lower heat transfer zones 51, 52 intothe downstream intermediate heat transfer zones 53, 54 or all of theintermediate and upper heat transfer zones 53, 54, 55, and 56.

In another embodiment, in addition to or instead of such seriesconnection of the lower, intermediate, and upper heat transfer zones 51,52, 53, 54, 55, and 56, respectively, they are connected to each otherin parallel. In this other embodiment, inlets 75 of heat exchangers 70are connected to each other and outlets 78 are connected to each other,such that the heat transfer fluid 100 is divided and simultaneouslyflows through the respective heat exchanges 70.

Still referring to FIGS. 7, 8, and 10, regardless of the particularconnection type between the heat exchangers 70, the hardware connectingthem defines part of a diverter system 80 that controls flow of the heattransfer fluid 100. Diverter system 80 includes diverters 82 thatcontrol which one(s) of the lower, intermediate, and upper heat transferzones 51, 52, 53, 54, 55, and 56, respectively, that the heat transferfluid 100 can flow through, at any particular time. As shown in FIG. 4,diverters 82 are electromechanical valves that are actuated andcontrolled by controls 90. Controls 90 include an industrial computeror, e.g., a programmable logic controller (PLC), along withcorresponding software and suitable hardware that allow a user to inputoperating parameters, such as a target size of a batch of food product,or a target temperature for the processing of the food product, thetarget temperature including desired variations of the temperature overtime while processing a batch.

Still referring to FIGS. 7, 8, and 10, based on the information inputtedby the user, the controls 90 determine and command (i) whether to heator cool the heat transfer fluid 100 with a heating/cooling device 110,(ii) to what extent to heat or cool the heat transfer fluid 100 with theheat/cooling device 100, (iii) a suitable flow path of the heat transferfluid 100 through the lower, intermediate, and upper heat transfer zones51, 52, 53, 54, 55, and 56, respectively, and (iv) which of diverters 82to actuate to establish the desired, suitable, flow path through thelower, intermediate, and upper heat transfer zones 51, 52, 53, 54, 55,and 56, respectively. In one embodiment, the controls 90 include alookup table that has information about where a splash zone 120 (FIGS. 3and 8) may be located upon the shell 25, as a function of, e.g., theparticular type of food that will be the vat contents for a batch, theparticular target size of the batch, and corresponding performancecharacteristics of vat components such as shaft rotation speed of theagitator system for that particular type of food. The splash zone 120 isgenerally defined at a fill-height for the respective batch, in otherwords, at a height upon the sidewalls 14, 15 at which the vat contentsextends for the batch and may extend slightly above and below suchfill-height, for about four or fewer inches above and below the fillheight, optionally about 10 or fewer inches above and below the fillheight. Based on the position of the estimated splash zone 120, thecontrols can command the diverter system 80 to direct heated or cooledheat transfer fluid 100 only to the lower, intermediate, and upper heattransfer zones 51, 52, 53, 54, 55, and 56, respectively, that will bepositioned lower than the estimated splash zone 120, preventing any heattransfer fluid 100 from flowing through a lower, intermediate, and upperheat transfer zones 51, 52, 53, 54, 55, and 56, respectively, that isprovided at the same height upon the shell 25 as the splash zone 120 orhigher than the splash zone 120.

Accordingly and referring yet further to FIGS. 7, 8, and 10, processingof a batch of food product occurs in the following way. In arepresentative application, a user inputs information into controls 90,informing the system that a batch of cheese will be a target size thatcorresponds to the amount of milk which will be introduced into the vat7 for the batch. In one embodiment, that is sufficient information andthe controls 90 retrieve a corresponding target temperature for thebatch or target temperatures for different phases of the processing ofthe batch. In another embodiment, such target temperature(s) values areentered manually by the user. Based on the target temperature and/or thetarget size of the batch, the controls 90 determine a suitable flow paththrough the heat transfer system 50.

Still referring to FIGS. 7, 8, and 10, if the controls 90 determine thata target temperature is warm enough to burn milk that may splash orslosh onto the splash zone 120, then controls 90 determine a flow paththrough the heat transfer system 50 that deactivates or excludes anyheat transfer zones upon which the splash zone 120 is defined. Forexample, if the splash zone 120 projects or is defined at a height ofthe vat 7 that the upper heat transfer zones 55, 56 occupy, then thediverters 82 are actuated so that the heat transfer fluid 100 only flowsthrough the lower and intermediate heat transfer zones 51, 52, 53, 54,respectively, which are lower than the splash zone 120.

Operation of the zoned heat transfer system 50 as described aboveestablishes a temperature differential a location at or near the splashzone 120, namely a temperature differential between (i) the upper heattransfer zones 55, 56, and (ii) the lower and intermediate heat transferzones 51, 52, 53, 54, respectively. In this example, the upper heattransfer zones 55, 56 transmit heat at a lower rate, optionally not atall, to the side walls 14, than does the lower and intermediate heattransfer zones 51, 52, 53, 54, respectively. In one embodiment, atemperature differential is established by heating the upper heattransfer zones 55, 56 to some extent, although to a lower temperature(s)than the lower and/or intermediate heat transfer zones 51, 52, 53, 54,respectively, are heated. This may be done by introducing relativelycooler heat transfer fluid 100 or a lesser amount of the sametemperature heat transfer fluid 100 into the respective lower and upperheat transfer zones 51, 52, 53, 54, 55, 56, respectively, across whichthe temperature differential is established.

Various alternatives and embodiments are contemplated as being withinthe scope of the following claims particularly pointing out anddistinctly claiming the subject matter regarded as the invention.

1. A vat system for processing liquid or semi-liquid compositions,comprising: a vat that includes a bottom wall and side walls extendingupwardly from the bottom wall; a zoned heat transfer system selectivelytransmitting heat to or removing heat from different portions of atleast one of the bottom and side walls of the vat.
 2. The vat system ofclaim 1, the zoned heat transfer system further comprising at least onelower heat transfer zone and at least one upper heat transfer zone. 3.The vat system of claim 2, wherein a heat transfer fluid is directedthrough the at least one lower heat transfer zone and selectivelydirected from the lower heat transfer zone through the at least oneupper heat transfer zone.
 4. The vat system of claim 2, the zoned heattransfer system further comprising a pair of lower heat transfer zonesextending across the vat bottom wall and a pair of upper heat transferzones extending across a respective pair of the vat side walls.
 5. Thevat system of claim 4, the pair of upper heat transfer zones beingcontrolled independently from the pair of lower heat transfer zones fortransmitting heat to or removing heat from the sidewalls and bottom wallat different rates.
 6. The vat system of claim 5, wherein the pair ofupper heat transfer zones are fluidly connected to the pair of lowerheat transfer zones such that a heat transfer fluid that flows throughthe pair of lower heat transfer zones can be selectively directedthrough the pair of upper heat transfer zones.
 7. A vat system forprocessing liquid or semi-liquid compositions, comprising: a vat thatincludes a bottom wall and a side wall extending upwardly from thebottom wall; a zoned heat transfer system that includes multiple heattransfer zones defined within the vat and selectively transmitting heatto or removing heat from at least one of the bottom and side walls; aheat transfer fluid within the zoned heat transfer system and being (i)heated for transmitting heat to the at least one of the bottom and sidewalls of the vat, or (ii) unheated for removing heat from the at leastone of the bottom and side walls of the vat; and a diverter systemwithin the heat transfer system that selectively directs a flow of theheat transfer fluid through the multiple heat transfer zones.
 8. The vatsystem of claim 7, the multiple heat transfer zones including: a lowerheat transfer zone defined at the bottom wall of the vat; and an upperheat transfer zone defined at the side wall of the vat.
 9. The vatsystem of claim 8, wherein the diverter system is in fluid communicationwith both of the lower and upper heat transfer zones and selectivelydirects the heat transfer fluid to flow through (i) only the lower heattransfer zone, or (ii) both of the lower and upper heat transfer zones.10. The vat system of claim 9, the zoned heat transfer system includingmultiple upper heat transfer zones defined at the side wall and whereinthe diverter system includes a diverter that is provided between themultiple upper heat transfer zones and can be actuated to direct a flowof the heat transfer fluid through a single one of the multiple upperheat transfer zones.
 11. The vat system of claim 10, the heat transferzones including heat exchangers and each of the heat exchangers having(i) an inlet through which the heat transfer fluid enters the heatexchanger, and (ii) an outlet through which the heat transfer fluidexits the heat exchanger.
 12. The vat system of claim 11, wherein inletsof at least some of the heat exchangers are connected to each other,such that the heat transfer fluid enters the respective heat exchangersin parallel.
 13. The vat system of claim 11, wherein inlets of some ofthe heat exchangers are connected to respective outlets of others of theheat exchangers, such that the heat transfer fluid flows through therespective heat exchangers in series.
 14. A method of processing aliquid or semi-liquid composition in a vat, comprising: determining (i)a target size of a batch of the composition to be processed in a vat,and (ii) a target temperature for processing the batch of thecomposition within the vat; delivering a heat transfer fluid to a zonedheat transfer system of the vat for transmitting heat to or removingheat from the batch of the composition; and directing the heat transferfluid through the zoned heat transfer system along a flow path that isselected based on at least one of the target size and target temperatureof the batch of food product.
 15. The method of claim 14, furthercomprising: establishing a temperature differential between two heattransfer zones of the heat transfer system and through which the heattransfer fluid can be directed.
 16. The method of claim 15, wherein atemperature of one of the two heat transfer zones is heated or cooled toa temperature that defines a first component of the temperaturedifferential and that substantially corresponds to the targettemperature for processing the batch of the composition.
 17. The methodof claim 14, wherein the zoned heat transfer system includes multipleheat transfer zones and the heat transfer fluid is directed throughfewer than all of the multiple heat transfer zones.
 18. The method ofclaim 14, the multiple heat transfer zones including a lower heattransfer zone and an upper heat transfer zone, and wherein (i) the heattransfer fluid is directed through the lower and upper heat transferzones while processing a batch of food the composition with a relativelylarge target size, and (ii) the heat transfer fluid is directed throughthe lower heat transfer zone and diverted away from the upper heattransfer zone while processing a batch of the composition with arelatively small target size.
 19. The method of claim 18, whereinmultiple upper heat transfer zones are provided and the heat transferfluid can be directed through fewer than all of the multiple upper heattransfer zones.
 20. The method of claim 19, further comprisingsimultaneously diverting flow of the heat transfer fluid away from (i) afirst upper heat transfer zone associated with a first sidewall of thevat, and (ii) a second upper heat transfer zone associated with asecond, opposing sidewall of the vat.
 21. The method of claim 19,further comprising simultaneously directing flow of the heat transferfluid through pairs of heat transfer zones, each pair of heat transferzones including a first heat transfer zone and a second heat transferzone that are positioned as mirror images of each other as reflectedabout a longitudinally extending centerline of the vat.